Effective delivery of recombinant proteins to rod photoreceptors via lipid nanovesicles

• Recombinant proteins encapsulated in nano-sized liposomes injected intravitreally reach retinal photoreceptors.
• The phototransduction cascade in rods is modulated by the liposome content.
• Mathematical modeling predicts the alteration of the photoresponses following liposome fusion.

The potential of liposomes to deliver functional proteins in retinal photoreceptors and modulate their physiological response was investigated by two experimental approaches. First, we treated isolated mouse retinas with liposomes encapsulating either recoverin, an important endogenous protein operating in visual phototransduction, or antibodies against recoverin. We then intravitrally injected in vivo liposomes encapsulating either rhodamin B or recoverin and we investigated the distribution in retina sections by confocal microscopy. The content of liposomes was found to be released in higher amount in the photoreceptor layer than in the other regions of the retina and the functional effects of the release were in line with the current model of phototransduction. Our study sets the basis for quantitative investigations aimed at assessing the potential of intraocular protein delivery via biocompatible nanovesicles, with promising implications for the treatment of retinal diseases affecting the photoreceptor layer.